Absorption plant



ABSORPTION PLANT Filed Feb. v, 1923 AIMEE)? INVENTOR. CARL. E BEAM BY f T0 NEYS;

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Patent-ed Aug. 30, 1927.

UNITED STATES CARL F. BRAUN, OF PASADENA, CALIFORNIA.

ABSORPTION PLANT.

Apphcation filed February 7, 1923.

This 'i'vention relates to an absorption plant and a method oi operating the same.

it is the principal object of the present inrention to provide an absorption plant arrangement. particularly adapted for the recovery of gasoline from casing head gas, which plant is decidedly economical in its operation, and permits the advantageous use denuded oil to oil and of oil to water l1e-..t exchangers, thereby eliminating a considerable amount 01 expensive equipment, and at the same time facilitating in the recovery of asoline or like products, it being uade 3L ed that the plant is applicable for other uses than when acting upon casing head gases, and that in any event, the heat exchangers operate in a manner to insure that proper exchange of heat will be made, without the production of scale in the water circulating conduits ot' the apparatus, and without necessitating the use of other cooling mediums save the denuded oil produced incidental to the distillation and absorption operations.

It is an additional object of the present invention to provide means for insuring that the cooling medium will be maintained in a stable condition, for when water is used at high temperature in condensing and cooling apparatus, it is usually dillicult to regulate the temperature of the cooling or condensing suri'aces when this tem icrature is above the boiling temperature of the water, as this permits great fluctuation of temperature caused by vaporization of a portion of the water.

The present invention contemplates the use of an absorption tower, a still, and inter mediate heat exchangers, through which a flow oi saturated oil, denuded oil and water may be brought about and controlled in a manner to remove a desired product from the saturated oil, while varying its temperature as controlled by the intertiow oi denuded and saturated oil through heat exchangers, and the flow of water through certain other heat exchangers.

The invention is illustrated by way of example in the accompanying drawings, in which:

Fig. 1 is a view in diagram showing the schematic arrangement of. the absorption plant embodying a more complicated arrangement of the iresent invention, whereby more eiilcient results may be obtained.

Serial No. 817,494.

Fig. 52 is a view in diagram showing an alternate form of absorption plant, operating on the general plan of that disclosed in Fig. 1.

Referring more particularly toFig. 1, indicates an absorption tower, to the bottom of which casing head gas obtained from oil wells and the like is delivered through a pipe 11, and passes upwardly through the absorber. An absorption oil having boiling points above those of gasoline is pumped into the top of the absorber tower through a pipe 12, and is permitted to flow downwardly through the tower, passing over and around obstructions which bring it into intimate contact with the upwardly flowing casing head gas. This absorption oil is drawn oil atthe bottom of the absorber through a pipe 13 and in the form of a saturated oil is carried to a heat exchanger 14. This saturated oil contains various amounts of gasoline which have been absorbed from the gas while passing through the tower, and it is very common for the gasoline content of the oil to equal by weight of the amount of oil drawn from the tower. The saturated oil, after passing through heat exchanger 14 is then conducted through a conduit 15 to a heat exchanger 16, during which time its temperature is raised, and after which it is delivered to the top of a vertical still 17 through a conduit 18. This saturated oil containing the gasoline flows into the still at a comparatively high temperature, at which time steam is injected into the bottom of the still through the pipe 19, the quantity of steam frequently amounting to from to 100% by weightof the gasoline to be distilled oil. A steam heating coil 20 is mounted within the still to increase the temperature in the vaporizing space.

Due to the increased temperature of the saturated oil delivered to the still and the action produced by the reduced partial pressure of the gasoline vapors because of the injected steam, the gasoline will pass oil from the still as a vapor through outlet pipe 21. where it is condensed and cooled by some cooling medium such as water. In the arrangement shown in Fig. 1, it is noted that the gasoline vapors pass through the heat exchanger 16, said exchanger also being in the path of flow of the saturated oil as it travels to the still. The vapors passing from pipe 21 to the primary fractionating c ndenser ers cooled by water which flows through the 16 will be cooled as they pass through this condenser and will successively pass through the control fractionating condenser 22, thence along pipe 23 to the primary section 24 of the gasoline condenser and then along pipe 25 to the final. section 26 of the gasoline condenser, after which the condensed vapors will be drawn away to a storage tanl; through a pipe 2. The final condenser is cooled by water as a cooling; medium which passes into the condenser through pipe 28 and passes out through a pipe 29. During this operation the denuded oil is being drawn vfrom the bottom of the still 17 and is then passed through pipe 30 to the heat exchanger l-l, where a portion of the heat from the denuded oil will be imparted to the saturated oil flowing to the still. The denuded oil will then pass through a pipe 31 to oil intercooler and will then pass through pipe to the primary section 24 of the gasoline condenser. Attention is directed to the fact that after the denuded oil has passed through the intercooler 32 its ten'iperature will be appreciably lower than when it left. the neat exchanger and it is one of the inportant features of. the present invention to then take the denuded oil and use it a cooling medium during which time its temperature will rise, and after which its temperature may again be lowered to a temper..- tnre suitable for its delivery to the absorption tower. This is brought about by circulating the denuded oil through pipe 35 to the primary section 2t of the gasoline con denser, after which it is carried to control condenser 22 by pipe 86. In these two condensers the denuded oil will tend to cool the hot vapors which have been drawn from the still, and at the same time the temperature of the denuded oil will rise. This oil will then be conducted through pipe 37 to an oil, cooler 39, thereafter passing through pipe L0 to a. pump 41 and then returning to the absorber 10 through pipe 12. The eooland as indicated in Fig. 2 are coolers. entering by pipes 33 and leaving by pipe-s 3 t. The operation of: the apparatus shown in Fi 2 is slightly modified as compared with the arrangement shown in Fig.

1, although the same idea is carried out.

to w t. that an exchange of heat is brough abou at dil ferent'points in the apparatus and =en saturated and denuded. oil or some inen truuin. and theta iinal exchange takes place between the denuded menrtruiun and water a tenmeratnre beow the scaling temperature of the water. Referring more particularly to 2 it will. be seen that: the saturated oil passes from the tower 10 through pipe 13, thereafter passing through heat exchanger 1% where it flow. in heat exchange relationship to de nuded oil passing from the still 17,the result being that the temperature of the saturated oil will be raised prior to delivrrv of this oil to the still. The vapors passing from the still through pipe 21 will sitter flowing through the }l)lin'ltllfy fraetionatin condenser 16 then flow through the control fractionatinp conden'er a 'tter which these vapors will pass successively through the gasoline condenser 24 and the final condenser 26. The denuded oil which has been drawn oil "from the bottom of the still 17 passes successively through heat exchanger 14. oil intercoolers and 39, which inter-coolers are water cooled. and then through gasoline condensers 241i. and the control fract-iona ting condenser 22 thereafter flowing through the intercpolers and being drawn oh" to the tower 10 by the pump ll. By this means it will be seen that the denuded oil after herring been cooled through the intercoolers will cool the gaseous vapors flowing through the control tractionating condenser and the gasoline condenser and will permit linal condensation of the vapors to be eii'ected in the linal con denser 26 where water is used as a cooling medium.

It will be seen that the process here employed is a continuous one. Economic waste is involved in most plants in supplying: steam or other heat for raising the tom-- pe ature oi the oil. while at the same time acooling medium must be supplied 't'or rcmoving the heat from the vapors and. denuded oil passing); from the still. This is obviated in the present instance by the installation of economic waste heat excln apparatus by means oi which much oi heat to be removed from the denuded oi transmitted to saturated oil. thereby necting a saving 031' both the heating: niwliuni and the cooling medium.

One of the serious operating; ditticulties in absorption plants is the scalim; oft apparatus in which oil or vapor are cooled by means of water. The useoll heat exchanging); apparatus reduces this operating dillicult'y, due partly to the tact that less water cooled apparatus is required. but principally because the fluid to be cooled has been materially reduced in temperature before entering the water cooled appa *atus. It has been found from actual experience that ii the oil and vapors are reduced in temperature to 120 F. before entering the water cooled ap' paratus, objectionable scaling is eliminated, and with many waters a temperature of about 150 F. may be permitted without encountering objectionable scaling. This has been borne in mind in the present instance, as will be understood trom a study of the flow plan of the plants here indicated in dia gram, and as will be more fully understood as the operation of the invention is hereinafter set forth.

In operation of a typical plant embodying the invention it will be assumed that the temperature of the denuded oil is usually decreaed from 220 F. to 120 F., While passing through the absorption plant, and that the saturated oil temperature increases from 80 F. to 180 F., during its flow through the absorption plant. These temperatures are in the present instance controlled by the flow arrangement through the various heat exchangers and condensers here shown. Referring to Fig. 1 of the drawings, by way of example, it will be assumed that denuded oil is delivered to the absorber through pipe 12 at a temperature of 80 F., and that the saturated oil drawn off through pipe 13 is at asimilar temperature. This saturated oil is then delivered to the heat exchanger 1-1, where it will, of course, enter at a temperature of 80 F., and due to the circulation of denuded oil passing through the same exchanger, it will leave this exchanger at a temperature of approximately 180 F. This oil then passes through the primary tractionating condenser 16, leaving this condenser at a temperature of approximately 210 F., at which temperature it is delivered to the still. In some instances it will be understood that the arrangement of heat exchangers and condensers may be varied, as :tor example, in the use of a plural ity of heat exchangers, 1a, or a plurality of oil inter-coolers, such as 32 and 39, or the elimination of certain condensers, such as the primary tractionating condenser, 16, and the primary gasoline condenser, 24. Due to the delivery of steam to the vaporizing chamber of the still, the fluids within the still will have a temperature of approximately 220 F., at which temperature the oil will fall and the gasoline will pass ofi as a light vapor through pipe 21. The temperature of the gasoline will be approxi mately 220 F. A portion of this heat will be imparted to the counter flow of saturated oil pas ing through the condenser 16 to the still it this condenser is used. The cooling gasoline vapors will then pass successively to control condenser 22 and condenser 24 and 26, during which time the temperature will be lowered to approximately 80 F. While the gasoline vapors and condensate are pa sing through the condensers 22 and 24 there is a simultaneous counterfiow of denuded oil through the opposite sides of these condensers. This oil was withdrawn from the still at a temperature of approximately 220 F., thereafter passed through the heat exchanger 1 1-, where a part of its heat was imparted to the saturated oil flowcoolcr is below the scaling point of water,

thus making it possible to circulate water through the intercooler 32, delivering it at 75 F.. and carrying it off at approximately 100 without scaling. The denuded oil will then have a temperature of approximately 00 F.. and at this ten'lperature will be circulated in a counter direction through the condensers 21 and 22, respectively. During this flow the temperature of the denuded oil will he aga n raised to approximately 120 F.. at which temperature it will be ledelivered to the oil cooler 30. This oil cooler employs water asa cooling medium which is delivered at the normal temperature of approxin'iately 75 F. and is withdrawn at a temperature of 100 F. By this time the denuded oil will have reached a temperature of 80 F., and will be in suitable condition for delivery to the abso-rben. Attention is directed to the fact that during all this circulation the gasoline vapors and condensate have been lowered to a temperature of 120 F., when they leave the condenser 24. This makes it possible for the final condenser to use water as a cooling medium, without danger of scaling. lVater is therefore delivered through pipe 28 at a l'en'ipcratru'e of F.. and withdrawn through pipe 29. at a temperature of 100 F. The final product passing from the condenser 20 will have a temperature of approximately F. The control of the temperature is brought about to such a nicety in the present instance by regulating the flow of denuded oil through the condensers 22 and 24: by the control of bypass valves 42 and 88. This regulation may be brought about by varying the amount of opening of the valves 88 and 42, so that the denuded oil passing from inlercooler 32 and to control gasoline condenser 24 may be by pas ed from pipe to pipe 86 through valve 88 in a manner to decrease the velocity flow of denuded oil through gasoline condenser 24. The flow of oil through the fractionah ingcondenser 22 may also be controlled by varying the opening of 'alve 42 to permit all or part of the oil flowing through pipe 36 to be circulated through the control condenser 22. In any event, the final product will be obtained by th use of a minimum r 1 casing, head crease the temperature of the saturated oil trom the tcniperatiu'e at which it leaves the heat erchanger 14;, namely 180 F, to the temperature of the 'll, v1.2: 220 F.

Assuming that 4000 pounds per hour of he vapors at the rate of 2 1O0 pounds per hour, the total heat required to reduce the temperature of the vapors from 220 F to 120 ll. is approximately three n on u. there tore, the saturated oil were heated by the vapors in the vapor to oil exchanger to the still temperature, the temperature of the vapors would not be reduced to the desired 12( F. for delivery to a water cooled condenser. lit would. therefore be necessary to use water in comparatively high temperature vapor condensing apparatus, and scaling would surely result.

in absorption plants the condenser must alw s be divided into units, so that the characteristies of the gasoline produced may be controlled at will by regulation 01" the temperature in the linal unit or the condenser. The condensate from the other units of the condenser is returned to the still.

iissumii'ig that, in the use of the plant shown in the drawings, the same quantities oi. fluids as described above are circulated,

then 1,500,000 B. t. u. would be removed from the vapors by heating the saturated oil from 180 to 210 F, the remaining 1,- 500,000 B. t. 11. required to reduce the temperature of the vapors to 120 F. are removed by means of the denuded oil which I have previously cooled to say 90 F. I heat this denuded oil from 90F. to say 120 F.

i in. the vapor condensing apparatus and then it to the linal oil coolers where its temperature is reduced to say 80 F.

It will thus be seen that the present invention makes it possible to utilize denuded oil ine oi. the cooling mediums in an absorp tion plant, and water the other cooling, medium. without requiring a circulation of an additional quantity of oil as a cooling 1. A method of recovering gasoline from l claim rnd desire to secure lit." Letters Patand the like, which consists in passing denuded absorption oil through an abiorption tower in the presence of the gas, thereafter drawing oil the saturated absorption oil and passing it through a heat exchanger, where its temperature is raised, and thereafter delivering aid oil. to a still, through which ittlows while gaseous vapors are termed, then passii'ig; the denuded ab sorption oil drawn from the still through the heat exchanger to raise the temperature of the incoming saturated oil, thereafter passing he denuded oil through a primary gasoline condenser, where its temperature israised, and then passing said oil through a control. tractional condenser and returiu ingthe denuded absorption oil. to the absorptiou tower, at the same time drawing of? the gaseous-vapors from the still and passing; them in their highly heated condition through a primary tractionating condenser, where they will act to raise the temperature oi the saturated oil passing from the heatenchang'er to. the still, after which the gaseous vapors through the fractionatinp; control condenser, where a further trans er of heat will be madeto the denuded oilpassing from the primary gasoline condenser to the absorption tower and then passing the gaseous vapor through the primary gasoline condenser, while raising the ten'iperature ot-the denuded oil passing: trom an oil intercooler where it is cooled and then passes to the control fractional condenser.

0 method of producing gasoline from casing head gas and the like, whichconsists .111 oelivermg a denuded absorption oil to an absorption tower where it comes in intimate contactwith the gas, thereafter drawing; oil the saturated absorption oil from the tower and delivering it to a, still, during which flow said oil successively passes through a heat exchanger and a primary tractionating condenser, in. the first ot which its tcmnerature is raised by a flow of oil drawn from the bottom of the still. and in the second o'l which its temperature is further raised by an exchange of heat trom gaseous vapor drawn oil "from thestill. pziissing the gaseous vapor through a tractionatiug control courand a prii'uary gasoline condenser and passing the denuded oil which has been Ill) a still at a relatively high temperature, the saturated oil during its transit successively rough a plurality of heat exchangiwt ot' which also passes the iLlllHlWl oil drawn oil from the still at a relative; h licm iicraturc, and through the second ot which also passes the gaseous vapors drawn from the till at a relatively high tcnipcratarc, thereafter passing gaspors through a series ol condensers, sing the denuded oil drawn from the first heat exchanger through a water cooled heat exchanger and the condensers in a counterllow to the gaseous vapors whereby the gaseous; vapors will be cooled and then passing said cooled vapors through a condenser.

i. A method of producing gasoline from casing head gas and the like, which consists in delivering a denuded absorption oil to an absorption tower wherein it comes into intimate contact with the gas to be treated, thereafter drawing oil the saturated absorption oil at a relatively low temperature, then delivering one saturated absorption oil to a still at a relatively high temperature, the saturated oil during its transit successively passing through a. plurality of heat exchangers; through the first of which also was the denuded oil drawn otl' from the ll at a relatively high leinperature, and through the second ol which also passes the gaseous vapors drawn from the still at a relatively high temperature, thereafter passing gaseous vapors through a series of conpassing the denuded oil drawn from the hrst heat exchanger through a water cooled heat exchanger and the condensers in a counter-flow to the gaseous vapors whereby the gaseous vapors will be cooled, and then completing the condensation of the gas by passing it through a water cooled condenser.

5. A method of producing gasoline from casing head gas and the like, which consists in delivering a denuded absorption oil to an absorption tower wherein it comes into intii'nate contact with the gas to be treated, thereafter drawing off the saturated absorp tion oil at arelatively low temperature, then delivering the saturated absorption oil to a still at a relatively high temperature. the saturated oil during its transit successively passin through a plurality of heat exchangers. through the first of which also passes the denuded oil drawn oli' from the still at a relatively high temperature, and through the recond of which also passes the gaseous vapors drawn from the still at a relatively high temperature, thereafter passing gaseons vapors through a series of condensers, pas ing the denuded oil drawn from the first heat exchanger through a water cooled heat exchanger and the condensers in a countertlow to the gaseous vapors whereby the gaseous vapors will be cooled, and regulating the counter-flow of denuded oil to the condensers to bypass the oil around a condenser in a manner to obtain a desired cooling temperature in each of the condensers and finally condensing the vapors in a water-cooled condenser.

6. A method of producing gasoline from casing head gas and the like, which consists in delivering a denuded absorption oil to an absorption tower wherein it comes into intimate Contact with the gas to be treated, thereafter drawing oli' the saturated absorp tion oil at a relatively low temperature, then delivering the saturated absorption oil to a still at a relatively high emperature, the saturated oil during its transit successively passing through a plurality of heat exchangers, through the first of which also passes the denuded oil drawn oil' from the still at a relatively high temperature, and through the second of which also passes the gaseous vapors drawn from the still at a relatively high temperature, thereafter passing the gaseous vapors through a series of condensers, and passing the denuded oil drawn from the first heat exchanger through a water cooled heat exchanger and the condensers in a counter-flow to the gaseous vapors whereby the gaseous vapors will be cooled, and then completing the condensation of the gas by passing it through a water cooled condenser, and passing the denuded oil from the condensers through coolers prior to the delivery of said denuded oil to the absorption tower.

7. A method of producing gasoline from casing head gas and the like, which consists in delivering a denuded absorption oil to an absorption tower wherein it comes into intimate contact with the gas to be treated, thereafter drawing oil the saturated absorption oil at a relatively low temperature, then delivering the saturated absorption oil to a still at a relatively high ten'iperature, the saturated oil during its tansit successively passing through a plurality of heat exchangers, through the first of which also passes the denuded oil drawn oil from the still at a relatively high temperature, and through the second of which also passes the gaseous vapors drawn from the still at a relatively high temperature, thereafter passing gaseous vapors through a series of condensers, and passing the denuded oil drawn from the first heat exchanger through a water cooled heat exchanger and the condensers in a counter-.

flow to the gaseous vapors wl'iereby the gaseous vapors will be cooled, then finally condensing the vapors in a water-cooled con denser, the denuded oil passing through an intercooler prior to reaching the condensers.

S. A method of recovering gasoline from casing head gas, and the like, which conssts in passing denuded oil through an absorption device in the presence of the gas, where by saturated absorption oil of a relatively low temperature will be produced, therea'tter passing said saturated oil through heat exchangers in which the temperature of said oil will be raised, thenpassing the oil into a still, where gaseous vapors will be produced, to be drawn from the still, and the saturated oil will thus be denuded; then passing said denudedoil, whichis of relatively high temperature, through one of the heat exchangers through which the cooler saturated oil is flowing, whereby the temperature of the denuded oil will be lowered to a temperature approximately lower than the scaling point of water; then passing said denuded oil through a water cooler and thereafter passing the denuded oil through a control condenser while passing the gaseous vapors from the still through said condenser.

9. A method of recovering gasoline from casing head gas, and the like, which consists in passing denuded absorption oil through an absorption tower in the presence of the gas, thereafter drawing oil the saturated absorption oil and passing it through a heat exchanger, where its temperature is raised; then delivering said heated saturated oil to a still through which it flows w iile gaseous vapors are being formed; then drainingthe denuded absorption oil from the still and passing it through the heat excl'ianger through which the incoming saturated oil is flowing, and in which exchanger the saturated oil will be heated and the denuded oil cool-ed to a temperature approximating that of the scaling point of water; then pass ing said denuded oil through a water cooler where itsv temperature is further, lowered, thereafter passing said cooled denuded oil through a condenser in a counter current flow to that of the gaseous vapors passing from the still, whereby said vapors will be cooled, and then passing said oil through water condensers operating at a temperature approximating the scaling point of water, whereby the temperature of the denuded oil will be lowered, Jreparatory to its delivery to the absorption tower.

10. A method of absorption in which gasoline is recovered from natural gases,

which consists in saturating a denuded 1nenstruum in an absorber, thereafter carrying the saturated menstruum to a still where its vapors are given oii' at a relatively high temperature, and then condensing said vapors using water as a final cooling agent and employing the absorbing menstruum as an intermediate cooling agent between the still and the final vapor cooling water condenser at a temperature below the'scaling temperature of the water.

11. A method of absorption in which gasoline is recovered from natural gases, which consists in saturating a denuded menstruurn in an absorber, thereafter carrying said saturated menstruuin to a still where its vapors are given oil, then passing the denuded absorbing menstruuin successively in heat exchange relationship to the saturated 1nenstruum, and to water whereby the tempera ture of the denuded menstruum will be lowered without scaling of the water, thereafter using the cool-ed denuded Inenstruum as a cooling agent for the vapors given off from the still, and then recooling the denuded menstruum by passing it through an oil to water heat exchanger prior to redelivering it to the absorber.

CARL F. BRAUN. 

